Pictured Above: Werner van Niekerk, director of Agristar Macadamias.

Many South African crop farmers are capitalising on the global changes in dietary trends.

Macadamias are especially high in monounsaturated fat, fibre, minerals and vitamins and apart from in the snack market, are gaining in popularity for their suitability in food items such as spreads, butter, milk, ice cream as well as in the confectionery industry.

Macadamia saplings can take up to 18 months before they are ready for planting and on most farms, the first crop is usually expected in three to five years. Because only a limited number of nuts are produced by a single tree per season and due to the costs added by processing, diligent management of both input and production costs is a must.

At a recent media day, Agristar Director Werner van Niekerk told reporters different cultivars were under scrutiny as well as increased tree density, organic fertilisers, biological pest control methods and cover crops, to cement sustainability.

The young trees are very susceptible to damage and water stress, so care must be taken during establishment that the root system makes good contact with the soil, and that the trees are protected from wind.

He said the operation was combining the latest technology and innovation in a bid to farm in harmony with nature while simultaneously producing high quality nuts for the export market.

“Agristar adheres to strict environmental guidelines,” he said. “We are firmly focused on more environmentally-friendly farming methods and the reduction of our carbon footprint. We are looking for the best methods and farming practices to protect the soil health while we still want to produce safe, superior quality nuts at an optimum yield. We believe working with the environment is crucial to sustainable macadamia production in the long term. Our aim is to treat all our resources with respect and responsibility.”

Key aspects that are considered when planning a macadamia orchard include the site, soil requirements, the micro-climate, cultivar selection, land preparation, and plant

Van Niekerk added that the operation was based on scientific research focused on the natural characteristics of the macadamia tree to guide their sustainable production. “The combination of soil health, the ideal climate and professional on-farm practices all contribute towards the perfect macadamia nut for the market.”

For Agristar, macadamia farming is not based on a short-term profit outlook.  It is a 24/7 commitment towards the environment while producing quality nuts. “When we decided to focus more on biological farming practices, we knew we would have to overcome several challenges. Soil fertility was a problem in some areas, and we knew we could not do anything that would negatively affect our quality. We had to think outside the box to overcome these issues and rely on our own trials as well as research,” he said.

Soil and water are scarce resources and should be well-managed. Agristar is therefore using the best soil management practices, water conservation technology, and integrated pest management programmes.

“By staying abreast of best practices and using the latest technology, we ensure we use our water resources responsibly,” said Anton Louw, Agristar farm manager. “We use low-flow drip irrigation with a flow of 0,7 l/h, with value-added mulch. Probes are used to monitor the soil and determine water requirements.  Since we implemented these practices we have realised water savings of 50%-60%.  We only irrigate our orchards when needed.”

Using greener energy is also part of the environmental focus. A solar powered pump system directs the irrigation water to the orchards.

Establishing a macadamia orchard is a costly exercise and mistakes during this phase could adversely affect the tree health and yield in later years. Mulch helps with moisture retention and new tree establishment. The lower water flow-drip irrigation system on the farm uses less water.

Most soil types are suitable for macadamia farming but must be drained and free from restrictive layers in the first metre of soil. According to Louw, they establish new orchards on areas that were previously used for forestry. He added that macadamia trees grow best in rich, well-drained soil and that they were lucky to mostly have Hutton soils, which have very good water retention ability. “The forestry, however, depleted the soils of nutrients, and water penetration is a problem. Once we have broken the crust that formed on these areas, the water penetration is much better.”

Newly established macadamia orchards near White River. The trees were planted on the contour lines on the slopes, with ridges to contain water run-off to minimise water and soil erosion during heavy rainfall.

Addressing soil health is a long process but with the actions they are implementing, they have been able to reduce their nitrogen applications by 20% per year to the point where they just apply the bare minimum. Applications of fertiliser and water are timed according to the needs of the tree at a given point in their phenological cycle.  Ridges built on the slopes also reduce water run-off and soil erosion.

Louw said they plant inter-row cover crops in the orchards to assist with water penetration and retention and to reduce evaporation. This ensures the water that is applied goes where it is needed: into the soil. “Our cover crops have the added benefit of supporting pollinator and pest control predators. This encourages an independent natural ecosystem reducing our need for water, soil additives, and chemical inputs. In addition, it also reduces our carbon footprint,” he added.

: Pruning is a positive management tool in intensive macadamia production. It allows light penetration to stress the tree for flower development, and also manages tree height. Werner van Niekerk, director Agristar Macadamias, explains to Lindi Botha, Target Communication, how pruning can increase light and air movement in the centre of the trees.

Some challenges had to be overcome when they started to plant the cover crops. “We are not row crop specialists, but did some research, talked to row crop experts and then bought a planter. We had to make a mind shift and focus on our vision, production and environmental goals,” Van Niekerk said.

They plant sunflower, also a nitrogen binder, which has roots that penetrate the soil and also attracts bees, as a cover crop in combination with others, like hemp and forage sorghum.  They are still experimenting with different plants in the cover crop mix to determine which will give the best results.

Strong winds are a problem in the area and can cause a great deal of damage to the macadamia trees, but because the cover crops grow quite tall, they add an additional benefit as they help protect the trees from the elements.

The cover crops are planted in early summer and cut down in autumn before it dries down completely, to reduce the risk of fire. The harvested material is then used for mulching. The areas between the trees are mowed and the material is blown under the trees and between them.

Macadamias need lots of organic matter, so the incorporation of as much compost as possible before planting is an added benefit, especially on sandy soils and those subjected to years of cultivation or forestry before macadamia establishment. “The application of a mulch, either as a cover or composted organic mulch, retains soil moisture and reduces weed growth. It also supplements organic and active carbon, which in turn supports and enhances feeder root growth. The cover crops and mulching are building life, structure and balance in our soils,” Louw said.

The precision planting practices do not end with soil health and water use. Using drones, they can ascertain the health of each tree in the orchard and consequently address problems before they affect the health of the entire orchard. They also focus on the poorest areas in the orchard to increase the average yield. All of the tractors as well as the applicators are fitted with GPS devices. “GPS allows us to do many of our farming operations more accurately and to optimally use our inputs and resources,” he added.

A common challenge in macadamia production is limiting physiological flower and nut drop caused by stress. Improved nut set in combination with increased resistance to physiological stress has a significant impact on final yield and crop quality.

Looking at optimum yield and production, they are moving towards a 4 x 2m planting system where they will have more trees per hectare but in contrast to older orchards, also much smaller trees. They have found that where they increased the number of trees to 1 250 per ha they were able to increase yields. The industry norm is about 2,7 t/ha and they are realising approximately 3,5 t/ha.

Although the input costs are much higher to establish a new high-density orchard, in time the increase in yield and profit will balance out the initial costs. They anticipate that the new practices will bring the trees into production must faster and help them to reach the break-even point earlier.

They are planning to plant certain cultivars on trellises for better light penetration. At present they prune the older trees for light penetration.

With an eye on the export market and MRL (minimum residue levels) concerns, their biological farming systems fit very well into their sustainable integrated pest management (IPM) programme, which is based on an ecosystem approach focused on long-term, sustainable solutions for managing pests. They want to reduce the use of non-selective chemicals and for a minimal impact on the environment and human health, they opt for alternatives such as hand slashers or brush cutters.

To obtain this goal, they firstly prioritise soil and tree health to limit the use of chemical pesticides and herbicides. They apply as few chemical pesticides as possible and rather rely on natural predators to control pests. Biological and mechanical weed and pest management is supplemented with soft organic products.

“Pest management is an integrated process and we have found through regular scouting, reactive management and encouraging a balanced ecosystem, we keep intervention to a minimum without sacrificing quality. In addition, bug hotels and predator havens assist indigenous pollinators and pest predators to thrive in our orchards,” explained Adriaan Heydenrych, the entomologist employed by Agristar.

Bees are important for the pollination of macadamia flowers and precisely for that reason, they have their own bee management programme and manufacture their own beehives. About 400 hives and 120 swarms have been installed on all Agristar farms. To support the bees, they plant bee gardens near the hives as well as bee-friendly cover crops to ensure the bees have food all year round. Just before the macadamia flowering season starts, the flowers and plants in the bee gardens are cut down and the bees move to the orchards to forage for food and in return also pollinate the macadamia flowers.

In addition to their integrated farming methods that focus on the natural biological system, they continuously remove alien vegetation so that the natural fauna and flora can thrive, and are involved in a programme to plant more indigenous trees that naturally occur in the area. All Agristar farms have indigenous wildlife reserves to support the wildlife in the area.

Nature conservation is close to their hearts. In the undeveloped areas of their farms, Agristar preserves ecological and wildlife havens. Besides the natural vegetation in these areas, wildlife is encouraged as natural grazers and browsers of the bushveld.

They are privileged to have three crowned eagle nests within the eco-reserves of Agristar’s farms and according to the team, it is very rewarding to continuously monitor the nests to ensure these wonderful birds of prey are looked after.  Visit to learn more.

“We base our farming on a very simple philosophy,” Van Niekerk said. “We want to leave a legacy. We are the custodians of the land. So, when we do our planning, we ask ourselves if we believe in what we are doing and if we wish to do good. If the answers are yes, then we determine if what we want to do maybev to the detriment of the environment and our farming enterprise. If the answer is no, then we follow our dreams.”